\FBMYSQLDUMP\FR

NAME

mysqldump - a database backup program

SYNOPSIS

mysqldump [options] [db_name [tbl_name ...]]

DESCRIPTION

The
mysqldump
client is a utility that performs
logical backups, producing a set of SQL statements that can be run to reproduce the original schema objects, table data, or both. It dumps one or more MySQL database for backup or transfer to another SQL server. The
mysqldump
command can also generate output in CSV, other delimited text, or XML format.

mysqldump
requires at least the
SELECT
privilege for dumped tables,
SHOW VIEW
for dumped views,
TRIGGER
for dumped triggers, and
LOCK TABLES
if the
--single-transaction
option is not used. Certain options might require other privileges as noted in the option descriptions.

To reload a dump file, you must have the same privileges needed to create each of the dumped objects by issuing
CREATE
statements manually.

mysqldump
output can include
ALTER DATABASE
statements that change the database collation. These may be used when dumping stored programs to preserve their character encodings. To reload a dump file containing such statements, the
ALTER
privilege for the affected database is required.
Performance and Scalability Considerations.PP
mysqldump
advantages include the convenience and flexibility of viewing or even editing the output before restoring. You can clone databases for development and DBA work, or produce slight variations of an existing database for testing. It is not intended as a fast or scalable solution for backing up substantial amounts of data. With large data sizes, even if the backup step takes a reasonable time, restoring the data can be very slow because replaying the SQL statements involves disk I/O for insertion, index creation, and so on.

For large-scale backup and restore, a
physical
backup is more appropriate, to copy the data files in their original format that can be restored quickly:

*
If your tables are primarily
InnoDB
tables, or if you have a mix of
InnoDB
and
MyISAM
tables, consider using the
mysqlbackup
command of the MySQL Enterprise Backup product. (Available as part of the Enterprise subscription.) It provides the best performance for
InnoDB
backups with minimal disruption; it can also back up tables from
MyISAM
and other storage engines; and it provides a number of convenient options to accommodate different backup scenarios. See
Section 25.2, lqMySQL Enterprise Backuprq.

*
If your tables are primarily
MyISAM
tables, consider using the
mysqlhotcopy
instead, for better performance than
mysqldump
of backup and restore operations. See
mysqlhotcopy(1).

mysqldump
can retrieve and dump table contents row by row, or it can retrieve the entire content from a table and buffer it in memory before dumping it. Buffering in memory can be a problem if you are dumping large tables. To dump tables row by row, use the
--quick
option (or
--opt, which enables
--quick). The
--opt
option (and hence
--quick) is enabled by default, so to enable memory buffering, use
--skip-quick.

If you are using a recent version of
mysqldump
to generate a dump to be reloaded into a very old MySQL server, use the
--skip-opt
option instead of the
--opt
or
--extended-insert
option.

For additional information about
mysqldump, see
Section 7.4, lqUsing mysqldump for Backupsrq.
Syntax.PP
There are in general three ways to use
mysqldump---in order to dump a set of one or more tables, a set of one or more complete databases, or an entire MySQL server---as shown here:

To dump entire databases, do not name any tables following
db_name, or use the
--databases
or
--all-databases
option.

To see a list of the options your version of
mysqldump
supports, issue the command
mysqldump --help.
Option Syntax - Alphabetical Summary.PP
mysqldump
supports the following options, which can be specified on the command line or in the
[mysqldump]
and
[client]
groups of an option file. For information about option files used by MySQL programs, see
Section 4.2.6, lqUsing Option Filesrq.
Connection Options.PP
The
mysqldump
command logs into a MySQL server to extract information. The following options specify how to connect to the MySQL server, either on the same machine or a remote system.

*
--bind-address=ip_address

On a computer having multiple network interfaces, use this option to select which interface to use for connecting to the MySQL server.

This option is supported beginning with MySQL 5.6.1.

*
--compress,
-C

Compress all information sent between the client and the server if both support compression.

Dump data from the MySQL server on the given host. The default host is
localhost.

*
--login-path=name

Read options from the named login path in the
.mylogin.cnf
login file. A
lqlogin pathrq
is an option group that permits only a limited set of options:
host,
user, and
password. Think of a login path as a set of values that indicate the server host and the credentials for authenticating with the server. To create the login path file, use the
mysql_config_editor
utility. See
mysql_config_editor(1). This option was added in MySQL 5.6.6.

*
--password[=password],
-p[password]

The password to use when connecting to the server. If you use the short option form (-p), you
cannot
have a space between the option and the password. If you omit the
password
value following the
--password
or
-p
option on the command line,
mysqldump
prompts for one.

Specifying a password on the command line should be considered insecure. See
Section 6.1.2.1, lqEnd-User Guidelines for Password Securityrq. You can use an option file to avoid giving the password on the command line.

*
--pipe,
-W

On Windows, connect to the server using a named pipe. This option applies only if the server supports named-pipe connections.

*
--plugin-dir=path

The directory in which to look for plugins. It may be necessary to specify this option if the
--default-auth
option is used to specify an authentication plugin but
mysqldump
does not find it. See
Section 6.3.7, lqPluggable Authenticationrq.

*
--port=port_num,
-P port_num

The TCP/IP port number to use for the connection.

*
--protocol={TCP|SOCKET|PIPE|MEMORY}

The connection protocol to use for connecting to the server. It is useful when the other connection parameters normally would cause a protocol to be used other than the one you want. For details on the permissible values, see
Section 4.2.2, lqConnecting to the MySQL Serverrq.

*
--secure-auth

Do not send passwords to the server in old (pre-4.1) format. This prevents connections except for servers that use the newer password format. This option is enabled by default; use
--skip-secure-auth
to disable it. This option was added in MySQL 5.6.17.

Note
Passwords that use the pre-4.1 hashing method are less secure than passwords that use the native password hashing method and should be avoided. Pre-4.1 passwords are deprecated and support for them will be removed in a future MySQL release. For account upgrade instructions, see
Section 6.3.8.3, lqMigrating Away from Pre-4.1 Password Hashing and the mysql_old_password Pluginrq.

*
--socket=path,
-S path

For connections to
localhost, the Unix socket file to use, or, on Windows, the name of the named pipe to use.

*
--ssl*

Options that begin with
--ssl
specify whether to connect to the server using SSL and indicate where to find SSL keys and certificates. See
Section 6.3.10.4, lqSSL Command Optionsrq.

*
--user=user_name,
-u user_name

The MySQL user name to use when connecting to the server.

You can also set the following variables by using
--var_name=value
syntax:

*
max_allowed_packet

The maximum size of the buffer for client/server communication. The default is 24MB, the maximum is 1GB.

*
net_buffer_length

The initial size of the buffer for client/server communication. When creating multiple-row
INSERT
statements (as with the
--extended-insert
or
--opt
option),
mysqldump
creates rows up to
net_buffer_length
length. If you increase this variable, ensure that the
net_buffer_length
variable in the MySQL server is at least this large.

Option-File Options.PP
These options are used to control which option files to read.

*
--defaults-extra-file=file_name

Read this option file after the global option file but (on Unix) before the user option file. If the file does not exist or is otherwise inaccessible, an error occurs.
file_name
is interpreted relative to the current directory if given as a relative path name rather than a full path name.

*
--defaults-file=file_name

Use only the given option file. If the file does not exist or is otherwise inaccessible, an error occurs.
file_name
is interpreted relative to the current directory if given as a relative path name rather than a full path name.

*
--defaults-group-suffix=str

Read not only the usual option groups, but also groups with the usual names and a suffix of
str. For example,
mysqldump
normally reads the
[client]
and
[mysqldump]
groups. If the
--defaults-group-suffix=_other
option is given,
mysqldump
also reads the
[client_other]
and
[mysqldump_other]
groups.

*
--no-defaults

Do not read any option files. If program startup fails due to reading unknown options from an option file,
--no-defaults
can be used to prevent them from being read.

The exception is that the
.mylogin.cnf
file, if it exists, is read in all cases. This permits passwords to be specified in a safer way than on the command line even when
--no-defaults
is used. (.mylogin.cnf
is created by the
mysql_config_editor
utility. See
mysql_config_editor(1).)

*
--print-defaults

Print the program name and all options that it gets from option files.

DDL Options.PP
Usage scenarios for
mysqldump
include setting up an entire new MySQL instance (including database tables), and replacing data inside an existing instance with existing databases and tables. The following options let you specify which things to tear down and set up when restoring a dump, by encoding various DDL statements within the dump file.

*
--add-drop-database

Add a
DROP DATABASE
statement before each
CREATE DATABASE
statement. This option is typically used in conjunction with the
--all-databases
or
--databases
option because no
CREATE DATABASE
statements are written unless one of those options is specified.

*
--add-drop-table

Add a
DROP TABLE
statement before each
CREATE TABLE
statement.

*
--add-drop-trigger

Add a
DROP TRIGGER
statement before each
CREATE TRIGGER
statement.

*
--all-tablespaces,
-Y

Adds to a table dump all SQL statements needed to create any tablespaces used by an
NDB
table. This information is not otherwise included in the output from
mysqldump. This option is currently relevant only to MySQL Cluster tables.

*
--no-create-db,
-n

This option suppresses the
CREATE DATABASE
statements that are otherwise included in the output if the
--databases
or
--all-databases
option is given.

*
--no-create-info,
-t

Do not write
CREATE TABLE
statements that re-create each dumped table.

Note
This option does
not
not exclude statements creating log file groups or tablespaces from
mysqldump
output; however, you can use the
--no-tablespaces
option for this purpose.

*
--no-tablespaces,
-y

This option suppresses all
CREATE LOGFILE GROUP
and
CREATE TABLESPACE
statements in the output of
mysqldump.

Permit creation of column names that are keywords. This works by prefixing each column name with the table name.

*
--comments,
-i

Write additional information in the dump file such as program version, server version, and host. This option is enabled by default. To suppress this additional information, use
--skip-comments.

*
--debug[=debug_options],
-# [debug_options]

Write a debugging log. A typical
debug_options
string is
d:t:o,file_name. The default value is
d:t:o,/tmp/mysqldump.trace.

*
--debug-check

Print some debugging information when the program exits.

*
--debug-info

Print debugging information and memory and CPU usage statistics when the program exits.

*
--dump-date

If the
--comments
option is given,
mysqldump
produces a comment at the end of the dump of the following form:

-- Dump completed on DATE

However, the date causes dump files taken at different times to appear to be different, even if the data are otherwise identical.
--dump-date
and
--skip-dump-date
control whether the date is added to the comment. The default is
--dump-date
(include the date in the comment).
--skip-dump-date
suppresses date printing.

*
--force,
-f

Continue even if an SQL error occurs during a table dump.

One use for this option is to cause
mysqldump
to continue executing even when it encounters a view that has become invalid because the definition refers to a table that has been dropped. Without
--force,
mysqldump
exits with an error message. With
--force,
mysqldump
prints the error message, but it also writes an SQL comment containing the view definition to the dump output and continues executing.

*
--log-error=file_name

Log warnings and errors by appending them to the named file. The default is to do no logging.

*
--skip-comments

See the description for the
--comments
option.

*
--verbose,
-v

Verbose mode. Print more information about what the program does.

Help Options.PP
The following options display information about the
mysqldump
command itself.

*
--help,
-?

Display a help message and exit.

*
--version,
-V

Display version information and exit.

Internationalization Options.PP
The following options change how the
mysqldump
command represents character data with national language settings.

*
--character-sets-dir=path

The directory where character sets are installed. See
Section 10.5, lqCharacter Set Configurationrq.

*
--default-character-set=charset_name

Use
charset_name
as the default character set. See
Section 10.5, lqCharacter Set Configurationrq. If no character set is specified,
mysqldump
uses
utf8.

*
--no-set-names,
-N

Turns off the
--set-charset
setting, the same as specifying
--skip-set-charset.

*
--set-charset

Add
SET NAMES default_character_set
to the output. This option is enabled by default. To suppress the
SET NAMES
statement, use
--skip-set-charset.

Replication Options.PP
The
mysqldump
command is frequently used to create an empty instance, or an instance including data, on a slave server in a replication configuration. The following options apply to dumping and restoring data on replication master and slave servers.

*
--apply-slave-statements

For a slave dump produced with the
--dump-slave
option, add a
STOP SLAVE
statement before the
CHANGE MASTER TO
statement and a
START SLAVE
statement at the end of the output.

*
--delete-master-logs

On a master replication server, delete the binary logs by sending a
PURGE BINARY LOGS
statement to the server after performing the dump operation. This option automatically enables
--master-data.

*
--dump-slave[=value]

This option is similar to
--master-data
except that it is used to dump a replication slave server to produce a dump file that can be used to set up another server as a slave that has the same master as the dumped server. It causes the dump output to include a
CHANGE MASTER TO
statement that indicates the binary log coordinates (file name and position) of the dumped slave's master. These are the master server coordinates from which the slave should start replicating.

--dump-slave
causes the coordinates from the master to be used rather than those of the dumped server, as is done by the
--master-data
option. In addition, specfiying this option causes the
--master-data
option to be overridden, if used, and effectively ignored.

The option value is handled the same way as for
--master-data
(setting no value or 1 causes a
CHANGE MASTER TO
statement to be written to the dump, setting 2 causes the statement to be written but encased in SQL comments) and has the same effect as
--master-data
in terms of enabling or disabling other options and in how locking is handled.

This option causes
mysqldump
to stop the slave SQL thread before the dump and restart it again after.

In conjunction with
--dump-slave, the
--apply-slave-statements
and
--include-master-host-port
options can also be used.

*
--include-master-host-port

For the
CHANGE MASTER TO
statement in a slave dump produced with the
--dump-slave
option, add
MASTER_HOST
and
MASTER_PORT
options for the host name and TCP/IP port number of the slave's master.

*
--master-data[=value]

Use this option to dump a master replication server to produce a dump file that can be used to set up another server as a slave of the master. It causes the dump output to include a
CHANGE MASTER TO
statement that indicates the binary log coordinates (file name and position) of the dumped server. These are the master server coordinates from which the slave should start replicating after you load the dump file into the slave.

If the option value is 2, the
CHANGE MASTER TO
statement is written as an SQL comment, and thus is informative only; it has no effect when the dump file is reloaded. If the option value is 1, the statement is not written as a comment and takes effect when the dump file is reloaded. If no option value is specified, the default value is 1.

This option requires the
RELOAD
privilege and the binary log must be enabled.

The
--master-data
option automatically turns off
--lock-tables. It also turns on
--lock-all-tables, unless
--single-transaction
also is specified, in which case, a global read lock is acquired only for a short time at the beginning of the dump (see the description for
--single-transaction). In all cases, any action on logs happens at the exact moment of the dump.

It is also possible to set up a slave by dumping an existing slave of the master, using the
--dump-slave
option, which overrides
--master-data
and causes it to be ignored if both options are used.

This option enables control over global transaction ID (GTID) information written to the dump file, by indicating whether to add a
SET @@global.gtid_purged
statement to the output.

The following table shows the permitted option values. The default value is
AUTO.

Value

Meaning

OFF

Add no SET statement to the output.

ON

Add a SET statement to the output. An error occurs if
GTIDs are not enabled on the server.

AUTO

Add a SET statement to the output if GTIDs are
enabled on the server.

This option was added in MySQL 5.6.9.

Format Options.PP
The following options specify how to represent the entire dump file or certain kinds of data in the dump file. They also control whether certain optional information is written to the dump file.

Produce output that is more compatible with other database systems or with older MySQL servers. The value of
name
can be
ansi,
mysql323,
mysql40,
postgresql,
oracle,
mssql,
db2,
maxdb,
no_key_options,
no_table_options, or
no_field_options. To use several values, separate them by commas. These values have the same meaning as the corresponding options for setting the server SQL mode. See
Section 5.1.7, lqServer SQL Modesrq.

This option does not guarantee compatibility with other servers. It only enables those SQL mode values that are currently available for making dump output more compatible. For example,
--compatible=oracle
does not map data types to Oracle types or use Oracle comment syntax.

This option requires a server version of 4.1.0 or higher. With older servers, it does nothing.

*
--complete-insert,
-c

Use complete
INSERT
statements that include column names.

*
--create-options

Include all MySQL-specific table options in the
CREATE TABLE
statements.

This option is used with the
--tab
option and has the same meaning as the corresponding
LINES
clause for
LOAD DATA INFILE. See
Section 13.2.6, lqLOAD DATA INFILE Syntaxrq.

*
--quote-names,
-Q

Quote identifiers (such as database, table, and column names) within
lq`rq
characters. If the
ANSI_QUOTES
SQL mode is enabled, identifiers are quoted within
lq"rq
characters. This option is enabled by default. It can be disabled with
--skip-quote-names, but this option should be given after any option such as
--compatible
that may enable
--quote-names.

*
--result-file=file_name,
-r file_name

Direct output to a given file. This option should be used on Windows to prevent newline
lq\nrq
characters from being converted to
lq\r\nrq
carriage return/newline sequences. The result file is created and its previous contents overwritten, even if an error occurs while generating the dump.

*
--tab=path,
-T path

Produce tab-separated text-format data files. For each dumped table,
mysqldump
creates a
tbl_name.sql
file that contains the
CREATE TABLE
statement that creates the table, and the server writes a
tbl_name.txt
file that contains its data. The option value is the directory in which to write the files.

Note
This option should be used only when
mysqldump
is run on the same machine as the
mysqld
server. You must have the
FILE
privilege, and the server must have permission to write files in the directory that you specify.

By default, the
.txt
data files are formatted using tab characters between column values and a newline at the end of each line. The format can be specified explicitly using the
--fields-xxx
and
--lines-terminated-by
options.

Column values are converted to the character set specified by the
--default-character-set
option.

*
--tz-utc

This option enables
TIMESTAMP
columns to be dumped and reloaded between servers in different time zones.
mysqldump
sets its connection time zone to UTC and adds
SET TIME_ZONE='+00:00'
to the dump file. Without this option,
TIMESTAMP
columns are dumped and reloaded in the time zones local to the source and destination servers, which can cause the values to change if the servers are in different time zones.
--tz-utc
also protects against changes due to daylight saving time.
--tz-utc
is enabled by default. To disable it, use
--skip-tz-utc.

*
--xml,
-X

Write dump output as well-formed XML.

NULL, 'NULL', and Empty Values: For a column named
column_name, the
NULL
value, an empty string, and the string value
'NULL'
are distinguished from one another in the output generated by this option as follows.

Value:

XML Representation:

NULL (unknown value)

<field name="column_name" xsi:nil="true" />

'' (empty string)

<field name="column_name"></field>

'NULL' (string value)

<field name="column_name">NULL</field>

The output from the
mysql
client when run using the
--xml
option also follows the preceding rules. (See
the section called lqMYSQL OPTIONSrq.)

Prior to MySQL 5.6.5, this option prevented the
--routines
option from working correctly---that is, no stored routines, triggers, or events could be dumped in XML format. (Bug #11760384, Bug #52792)

Filtering Options.PP
The following options control which kinds of schema objects are written to the dump file: by category, such as triggers or events; by name, for example, choosing which databases and tables to dump; or even filtering rows from the table data using a
WHERE
clause.

*
--all-databases,
-A

Dump all tables in all databases. This is the same as using the
--databases
option and naming all the databases on the command line.

Prior to MySQL 5.6.4, the
slave_master_info
and
slave_relay_log_info
tables (see
Section 17.2.2, lqReplication Relay and Status Logsrq) were not included by this option.

*
--databases,
-B

Dump several databases. Normally,
mysqldump
treats the first name argument on the command line as a database name and following names as table names. With this option, it treats all name arguments as database names.
CREATE DATABASE
and
USE
statements are included in the output before each new database.

*
--events,
-E

Include Event Scheduler events for the dumped databases in the output.

*
--ignore-table=db_name.tbl_name

Do not dump the given table, which must be specified using both the database and table names. To ignore multiple tables, use this option multiple times. This option also can be used to ignore views.

*
--no-data,
-d

Do not write any table row information (that is, do not dump table contents). This is useful if you want to dump only the
CREATE TABLE
statement for the table (for example, to create an empty copy of the table by loading the dump file).

*
--routines,
-R

Include stored routines (procedures and functions) for the dumped databases in the output. Use of this option requires the
SELECT
privilege for the
mysql.proc
table. The output generated by using
--routines
contains
CREATE PROCEDURE
and
CREATE FUNCTION
statements to re-create the routines. However, these statements do not include attributes such as the routine creation and modification timestamps. This means that when the routines are reloaded, they will be created with the timestamps equal to the reload time.

If you require routines to be re-created with their original timestamp attributes, do not use
--routines. Instead, dump and reload the contents of the
mysql.proc
table directly, using a MySQL account that has appropriate privileges for the
mysql
database.

Prior to MySQL 5.6.5, this option had no effect when used together with the
--xml
option. (Bug #11760384, Bug #52792)

*
--tables

Override the
--databases
or
-B
option.
mysqldump
regards all name arguments following the option as table names.

*
--triggers

Include triggers for each dumped table in the output. This option is enabled by default; disable it with
--skip-triggers.

*
--where='where_condition',
-w 'where_condition'

Dump only rows selected by the given
WHERE
condition. Quotes around the condition are mandatory if it contains spaces or other characters that are special to your command interpreter.

Examples:

--where="user='jimf'"
-w"userid>1"
-w"userid<1"

Performance Options.PP
The following options are the most relevant for the performance particularly of the restore operations. For large data sets, restore operation (processing the
INSERT
statements in the dump file) is the most time-consuming part. When it is urgent to restore data quickly, plan and test the performance of this stage in advance. For restore times measured in hours, you might prefer an alternative backup and restore solution, such as
MySQL Enterprise Backup
for
InnoDB-only and mixed-use databases, or
mysqlhotcopy
for
MyISAM-only databases.

Performance is also affected by the
transactional options, primarily for the dump operation.

*
--delayed-insert

For those nontransactional tables that support the
INSERT DELAYED
syntax, use that statement rather than regular
INSERT
statements.

As of MySQL 5.6.6,
DELAYED
inserts are deprecated, so this option will be removed in a future release.

*
--disable-keys,
-K

For each table, surround the
INSERT
statements with
/*!40000 ALTER TABLE tbl_name DISABLE KEYS */;
and
/*!40000 ALTER TABLE tbl_name ENABLE KEYS */;
statements. This makes loading the dump file faster because the indexes are created after all rows are inserted. This option is effective only for nonunique indexes of
MyISAM
tables.

*
--extended-insert,
-e

Use multiple-row
INSERT
syntax that include several
VALUES
lists. This results in a smaller dump file and speeds up inserts when the file is reloaded.

*
--insert-ignore

Write
INSERT IGNORE
statements rather than
INSERT
statements.

*
--opt

This option, enabled by default, is shorthand for the combination of
--add-drop-table--add-locks--create-options--disable-keys--extended-insert--lock-tables--quick--set-charset. It gives a fast dump operation and produces a dump file that can be reloaded into a MySQL server quickly.

Because the
--opt
option is enabled by default, you only specify its converse, the
--skip-opt
to turn off several default settings. See the discussion of
mysqldump option groups
for information about selectively enabling or disabling a subset of the options affected by
--opt.

*
--quick,
-q

This option is useful for dumping large tables. It forces
mysqldump
to retrieve rows for a table from the server a row at a time rather than retrieving the entire row set and buffering it in memory before writing it out.

*
--skip-opt

See the description for the
--opt
option.

Transactional Options.PP
The following options trade off the performance of the dump operation, against the reliability and consistency of the exported data.

*
--add-locks

Surround each table dump with
LOCK TABLES
and
UNLOCK TABLES
statements. This results in faster inserts when the dump file is reloaded. See
Section 8.2.2.1, lqSpeed of INSERT Statementsrq.

*
--flush-logs,
-F

Flush the MySQL server log files before starting the dump. This option requires the
RELOAD
privilege. If you use this option in combination with the
--all-databases
option, the logs are flushed
for each database dumped. The exception is when using
--lock-all-tables,
--master-data, or
--single-transaction: In this case, the logs are flushed only once, corresponding to the moment that all tables are locked. If you want your dump and the log flush to happen at exactly the same moment, you should use
--flush-logs
together with
--lock-all-tables,
--master-data, or
--single-transaction.

*
--flush-privileges

Add a
FLUSH PRIVILEGES
statement to the dump output after dumping the
mysql
database. This option should be used any time the dump contains the
mysql
database and any other database that depends on the data in the
mysql
database for proper restoration.

*
--lock-all-tables,
-x

Lock all tables across all databases. This is achieved by acquiring a global read lock for the duration of the whole dump. This option automatically turns off
--single-transaction
and
--lock-tables.

*
--lock-tables,
-l

For each dumped database, lock all tables to be dumped before dumping them. The tables are locked with
READ LOCAL
to permit concurrent inserts in the case of
MyISAM
tables. For transactional tables such as
InnoDB,
--single-transaction
is a much better option than
--lock-tables
because it does not need to lock the tables at all.

Because
--lock-tables
locks tables for each database separately, this option does not guarantee that the tables in the dump file are logically consistent between databases. Tables in different databases may be dumped in completely different states.

Some options, such as
--opt, automatically enable
--lock-tables. If you want to override this, use
--skip-lock-tables
at the end of the option list.

*
--no-autocommit

Enclose the
INSERT
statements for each dumped table within
SET autocommit = 0
and
COMMIT
statements.

*
--order-by-primary

Dump each table's rows sorted by its primary key, or by its first unique index, if such an index exists. This is useful when dumping a
MyISAM
table to be loaded into an
InnoDB
table, but makes the dump operation take considerably longer.

*
--shared-memory-base-name=name

On Windows, the shared-memory name to use, for connections made using shared memory to a local server. The default value is
MYSQL. The shared-memory name is case sensitive.

The server must be started with the
--shared-memory
option to enable shared-memory connections.

*
--single-transaction

This option sets the transaction isolation mode to
REPEATABLE READ
and sends a
START TRANSACTION
SQL statement to the server before dumping data. It is useful only with transactional tables such as
InnoDB, because then it dumps the consistent state of the database at the time when
START TRANSACTION
was issued without blocking any applications.

When using this option, you should keep in mind that only
InnoDB
tables are dumped in a consistent state. For example, any
MyISAM
or
MEMORY
tables dumped while using this option may still change state.

While a
--single-transaction
dump is in process, to ensure a valid dump file (correct table contents and binary log coordinates), no other connection should use the following statements:
ALTER TABLE,
CREATE TABLE,
DROP TABLE,
RENAME TABLE,
TRUNCATE TABLE. A consistent read is not isolated from those statements, so use of them on a table to be dumped can cause the
SELECT
that is performed by
mysqldump
to retrieve the table contents to obtain incorrect contents or fail.

The
--single-transaction
option and the
--lock-tables
option are mutually exclusive because
LOCK TABLES
causes any pending transactions to be committed implicitly.

To dump large tables, combine the
--single-transaction
option with the
--quick
option.

Option Groups

*
The
--opt
option turns on several settings that work together to perform a fast dump operation. All of these settings are on by default, because
--opt
is on by default. Thus you rarely if ever specify
--opt. Instead, you can turn these settings off as a group by specifying
--skip-opt, the optionally re-enable certain settings by specifying the associated options later on the command line.

*
The
--compact
option turns off several settings that control whether optional statements and comments appear in the output. Again, you can follow this option with other options that re-enable certain settings, or turn all the settings on by using the
--skip-compact
form.

When you selectively enable or disable the effect of a group option, order is important because options are processed first to last. For example,
--disable-keys--lock-tables--skip-opt
would not have the intended effect; it is the same as
--skip-opt
by itself.
Examples.PP
To make a backup of an entire database:

shell> mysqldump db_name > backup-file.sql

To load the dump file back into the server:

shell> mysql db_name < backup-file.sql

Another way to reload the dump file:

shell> mysql -e "source /path-to-backup/backup-file.sql" db_name

mysqldump
is also very useful for populating databases by copying data from one MySQL server to another:

This backup acquires a global read lock on all tables (using
FLUSH TABLES WITH READ LOCK) at the beginning of the dump. As soon as this lock has been acquired, the binary log coordinates are read and the lock is released. If long updating statements are running when the
FLUSH
statement is issued, the MySQL server may get stalled until those statements finish. After that, the dump becomes lock free and does not disturb reads and writes on the tables. If the update statements that the MySQL server receives are short (in terms of execution time), the initial lock period should not be noticeable, even with many updates.

For point-in-time recovery (also known as
lqroll-forward,rq
when you need to restore an old backup and replay the changes that happened since that backup), it is often useful to rotate the binary log (see
Section 5.2.4, lqThe Binary Logrq) or at least know the binary log coordinates to which the dump corresponds:

The
--master-data
and
--single-transaction
options can be used simultaneously, which provides a convenient way to make an online backup suitable for use prior to point-in-time recovery if tables are stored using the
InnoDB
storage engine.

For more information on making backups, see
Section 7.2, lqDatabase Backup Methodsrq, and
Section 7.3, lqExample Backup and Recovery Strategyrq.

*
To select the effect of
--opt
except for some features, use the
--skip
option for each feature. To disable extended inserts and memory buffering, use
--opt--skip-extended-insert--skip-quick. (Actually,
--skip-extended-insert--skip-quick
is sufficient because
--opt
is on by default.)

*
To reverse
--opt
for all features except index disabling and table locking, use
--skip-opt--disable-keys--lock-tables.

Restrictions.

mysqldump
does not dump the
INFORMATION_SCHEMA
or
performance_schema
database by default. To dump either of these, name it explicitly on the command line and also use the
--skip-lock-tables
option. You can also name them with the
--databases
option.

mysqldump
does not dump the MySQL Cluster
ndbinfo
information database.

Before MySQL 5.6.6,
mysqldump
does not dump the
general_log
or
slow_query_log
tables for dumps of the
mysql
database. As of 5.6.6, the dump includes statements to recreate those tables so that they are not missing after reloading the dump file. Log table contents are not dumped.

If you encounter problems backing up views due to insufficient privileges, see
Section D.5, lqRestrictions on Viewsrq
for a workaround.

COPYRIGHT

This documentation is free software; you can redistribute it and/or modify it only under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License.

This documentation is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with the program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or see http://www.gnu.org/licenses/.

SEE ALSO

For more information, please refer to the MySQL Reference Manual,
which may already be installed locally and which is also available
online at http://dev.mysql.com/doc/.